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Electron beam melting (EBM) is a 3D printing technology that, at first glance, appears very similar to\u00a0SLS 3D printing<\/a>. However, closer inspection reveals that EBM differs in several ways. The most significant differences are that the energy source comes from an electron beam instead of a CO2 laser and that the material used is conductive metal instead of thermoplastic polymer.<\/p>\n In particular, EBM often uses titanium alloys and isn\u2019t capable of printing plastic or ceramic parts. That\u2019s due to the fact that the technology is based on electrical charges. They are what produce the reaction between powder and electron beam, causing the former to solidify.<\/p>\n In the following, we\u2019ll take a closer look at EBM, including how it works, its pros and cons, as well as some ideal application areas.<\/p>\n All EBM 3D printers consist of an energy source capable of emitting the electron beam, a powder container, a powder feeder, a powder re-coater, and a heated build platform. Important to note is that the printing process must take place in a vacuum. That\u2019s because electrons of the electron beam would otherwise collide with gas molecules, which would \u201ckill\u201d the electron beam.<\/p>\n Pre-Printing<\/strong><\/p>\n Before the printing process can begin, the powder bin is filled with the desired metal powder. Once that\u2019s done, the powder bin is placed into the 3D printer, and the internal pressure is set to around 0.0001 mBar. Believe it or not, that\u2019s around 10 million times less than atmospheric pressure!<\/p>\n When the desired pressure is achieved in the build chamber, the electron beam is \u201cfired up\u201d, heating the build platform to high temperatures. For example, titanium requires 600\u2013700\u00b0C. After the build platform is heated, the printing process can finally start.<\/p>\n The Main Event<\/strong><\/p>\n The 3D printing itself starts with the powder re-coater, which deposits a single layer of preheated powder onto the build platform. Once the powder is set, it\u2019s time for the electron beam melting to begin. The electron beam is controlled by a set of electromagnetic coils, which accurately point the beam towards the desired points of the build platform. The electron beam moves selectively while melting the powder and causing the powder particles to fuse together.<\/p>\n After one layer is complete, the build platform is moved down one layer in height. The re-coater comes in again with a fresh layer of powder, and the electron beam starts to induce fusion of powder particles, causing the new layer to form. This process is repeated until the entire part is finished.<\/p>\n When finished, parts aren\u2019t immediately visible since they\u2019re inside the powder bin covered with semi-sintered powder, which must be removed.<\/p>\n Distortion<\/strong><\/p>\n The EBM 3D printing process involves high temperatures, which can be a problem for parts. If they are too hot for too long a time, they can distort. This is the main reason EBM requires supports, whose main function is to provide paths for excess heat to \u201cgo away\u201d and not to provide mechanical stability. Like SLS, the latter is provided by the semi-sintered powder that surrounds parts.<\/p>\n Interestingly, while high part temperatures are undesirable,\u00a0high surrounding temperatures\u00a0have a \u201cstress relief\u201d effect on the parts, helping to reduce the amount of distortion. This is a unique benefit only present with electron powder bed fusion systems.<\/p>\n Final Steps<\/strong><\/p>\n When parts are finally finished, the powder bin is taken out of the 3D printer. Despite the parts already being manufactured, you still can\u2019t use them yet. For starters, they have to be left to cool.<\/p>\n Despite the supports being made from the same metal material as the part itself, they\u2019re actually rather easy to simply break away. Afterward, EBM parts can be polished, coated, or machined using traditional techniques.<\/p>\n Just as with any other 3D printing technology, EBM also has its pros and cons.<\/p>\n Pros<\/strong><\/p>\n Cons<\/strong><\/p>\n An interesting fact about EBM 3D printing is that there are only a few companies making the 3D printers. One of the best known is\u00a0Arcam EBM<\/a>, a GE Additive company which, naturally, is a leader when EBM is concerned. Apart from Arcam, there\u2019s also Japan-based\u00a0JEOL<\/a>,\u00a0Freemelt<\/a>, as well as Chinese manufacturers, like\u00a0Sailong Metal<\/a>.<\/p>\n The prices for EBM 3D printers are high. We don\u2019t know the exact pricing, as it\u2019s not publicly available. Instead, we recommend contacting the respected manufacturers directly.<\/p>\n Since EBM 3D printers and powders are expensive, it\u2019s no wonder this technology isn\u2019t yet utilized for mass production. Instead, it\u2019s used for manufacturing a small series of parts which usually feature a complex structure.<\/p>\n As you\u2019d expect for a technology used for manufacturing high strength metal parts, it\u2019s used in a number of fields. EBM has already seen its use in medicine, aeronautics, and motorsports, to name a few.<\/p>\n One of the EBM applications worth pointing out was born in the medical industry. With EBM, it was possible to produce a fully functional, custom-made skull implant. As EBM parts are strong by default, this piece is for sure just as strong as the skull, or even stronger.<\/p>\nThe Printing Process<\/h3>\n
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Post-Processing<\/h3>\n
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Pros & Cons<\/h3>\n<\/div>\n<\/div>\n
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Industry & Applications<\/h3>\n
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